Elevator



Nov. 20, 1945. L w WACHTER 2,389,221

Nov. zo, 1945. L, w. WACHTER 2,389,221-

ELEvAToR A Filed Deo. 18, 1944 :s sheets-sheet 2 NOV- 20, 1945- wl.. w.IwAcl-rl-ER 2,389,221

ELEvAToR File-d Deo. 18, v1944 v s snqetssheet 5 Patented Nov.l 20, 1945y,

ELEVATOR Lester W. Wachter, Streator, Ill., assignor to Anthony Company,Streator, Ill., a corporation of Illinois Application December 18, 1944,Serial No. 568,606

17 Claims. (Cl. 214-77) This' invention relates to an elevating appayratus and primarily to a unitary assembly suitable for raising andloading loads. It has for one object to provide a movable platform forvehicles and to provide means for raising and lowering said platform.

Another object is to provide a unitary mounting for a vehicle gate whichfurnishes a support for a gate and means for raising and lowering it andwhich may be readily attached to a vehicle bodyas a unit.

Another object is to provide in connection with such a mechanism meansfor preventing overloading.

A still further object is to provide in connectiongwith such a mechanismlatching means for latching the gate or platform in the raised position.

Other objects will appear from time to time throughout the specificationand claims.

This invention is illustrated more or less diagrammatically in theaccompanying drawings wherein:

Figure 1 is a side elevation with parts broken away and parts in sectionshowing one form of the device;

Figure 2 is a side elevation taken on an enlarged scale and showing theplatform;

Figure 3 is an end view of the device of Figure 2;

Figure 4 is a plan view with parts broken away;

Figure 5 is a sectional view on a still further enlarged scale, taken atline 5, 5 of Figure 4, with parts in elevation showing one end of thecylinder assembly;

Figure 6 is a transverse sectional detail taken at line 8 6 of Figure 5;and

Figure 'I is a sectional detail taken on an enlarged scale at line `I1of Figure 2, and illustrating the latch mechanism used in one form oflock.

Like parts are indicated by like characters throughout the specificationand the drawings.

As shown the platform is mounted upon a vehicle, although it might bemounted upon any other v:form of support. The vehicle may include anyconventional form of frame and running gear. As shown there is a vehicleor chassis frame comprising longitudinal members I, I and one or moretransverse members 2. Ordinarily some form of body will be mounted yuponthe chassis frame, and as shown the body comprises side frame members 3and a iloor or other supporting surface 4. The vehicle will be supportedon wheels 5. The details of the vehicle suspension and'drive are notillustrated. as they form no essential part oi' the invention.

'I'he engine will generally be provided with a hood B and a cab 1 may beused if desired.

As a means for driving the raising mechanism a fluid pump 8 is provided,and it is driven by lany 4suitable means, but one convenient means is bya. shaft 9 which is itself 'driven from a power take-ofi of the engine.A sump or reservoir I0 is provided and it may have a member II which mayserve as a filler and also may be open to the air wholly or in parttopermit equalization of pressure within the sump as fluid is withdrawnfrom and returned to the sump. Intermediate the pump and the sump isprovided a valve housing I2 through which uid passes under pressure andwithin which a. pressure release is provided, so arranged that upon theoccurrence beyond a predetermined point uid is by-passed and returneddirectly to the sump. 'I'his serves as an overload check and preventsoverloading of the hoisting system. The details of the overload check orby-pass are not shown, as the by-pass might be omitted, and for thefurther reason that hydraulic overload checking means have beenheretofore used in other connections.

Fluid under pressure passes from the pump and through the overload checkby means of a high pressure supply pipe or line I3 and is returned tothe sump by a low pressure or return line or pipe I4.

The mechanism with the exception of the pump assembly and the supplylines is mounted as a unit and may be made as a separate unit andsubsequently applied to a vehicle or to another support. For thispurpose a. frame and support is provided to which the tail gate orplatform, the links which support it, and the cylinder are attached. Inthe particular form shown, the

' unitary supporting means comprises a transverse member I5 which asshown is of channel section but may have any desired shape. Oneconvenient means for attaching this member to a vehicle frame compriseslateral enlargements I6,

attached to or formed as a part of the member I5. These enlargements areperforated to receive bolts I1 which pass upwardly on each side ci' thevehicle frame member I and engage perforated transverse members I8 whichare positioned on the top of the vehicle frame members. The transversemember I5 serves as a support for the remainder of the mechanismwhichmakes up the supporting and raising andV lowering means for theplatform.

I9 is a hydraulic cylinder, which is provided with trunnions 28, 20.These trunnions are hollowand are received in bearings 2l, 2I carried bysupports 22, 22 which are secured to the transverse member i5. Thetrunnions and bearings are hollow and in each of them is positioned aconduit member 23 through which fluid enters and leaves the cylinder. Toone of the conduits 23 the inlet or high pressure pipe I3 is secured andto the other the outlet or low pressure pipe I4 is secured. These fluidconnections are of course concentric with the trunnions and bearings.Positioned within the cylinder I9 is a piston not shown, and a pistonrod 24 is secured to the piston and extends outwardly through thecylinder head 25. As shown, the piston rod is provided with a reducedportion 26 adjacent its outer end and is threaded. as at 21. The pistonand cylinder assembly may be of almost any desired construction.

' High pressure fluid is discharged through the pipe I3 and one of theconnections 23 and by valve means enclosed in the housing portion 28 maybe directed to the left side of the piston as seen in Figure 2, or thevalve may be positioned to permit fluid to be forced out of the cylinderby gravity when the gate is lowered. A connection 29 and a pipe 30 formpart of the fluid circuit. When the platform is to be raised, pressurefluid is directed through the pipe 30 and the connection 29 to theopposite side of the piston to force the pistonv inwardly along thecylinder and thus to raise the platform.' Adjacent its outer end thepiston rod is secured to the platform carrying mechanism in a mannerwhich will be described below. I

As a means for movably supporting the platform, the transverse member Iis provided with a pair of downwardly extensions 3l, 3|. Each of theseextensions may be reduced adjacent its lower` end, as at 32. Pivoted toeach of the portions 3|. as at 33, are arms 34. These arms may be of anyshape but as shown are generally tubular. Adjacent the outer'or free endof each of the arms is a curved portion 35.

Pivoted to the reduced portions 32 of each of the side members are arms36. While these arms may be so pivoted in any desired manner, in theparticular form here shown they are secured to a transverse member 31,which is itself pivoted, as at 31a, to the downward extensions 32 of theside members. Thus the arms 36 and the transverse member 31 form ineffect a unit. Fixed also to the member 31 is a pair of generallyparallel members 38. 39 is a transverse member secured adjacent theouter or free ends of the members 36, and to this member the outer endsof the members 38 are also secured. Adjacent the outer end of each ofthe members 36 a re duced portion 40 is secured. A transverse member 4Iis supported on trunnions 42 which are received in bearings 42apositioned in or supported upon the members 38, and the reduced outerend 26 of the piston rod 24 passes through and is secured to themember4I. Nuts 43 serve to secure the parts in adjustable position.

The platform might be formed in many different shapes and might embodymany different details of construction. That illustrated is one suitabledesign. A platform subframe comprises pairs of lateral members 44, 44which are secured together by any desired number of transverse members45. It will be noticed that the members 44 are extended upwardly, as at46. A transverse shaft 41 is mounted in the upper extensions 4.5

shaft 41. A second transverse shaft 48 is mount- I shaft 61.

ed in the lower portions of the members 44, and the members 40 which aresecured to the arms 36 are pivoted on that shaft. One of the transversemembers 45 may be tubular, as shown particularly in Figure 2.

The members 44 and 45, together with the transverse shafts 41 and 48,comprise what is in effect the backbone" of the platform. The tail gateproper is mounted upon and supported by this backbone," but is movablewith relation to it. The tail gate proper, therefore, comprises pairs oftransverse frame members 49 which are preferably spaced apart so thatthey can fit between the members 44. Additional end frame members 50-and side frame members 5I are provided for the tail gate itself. One ofthe members 5I may be provided with an extension or flange 52. Boardsvor other surface formed members 53 are secured to the frame which isformed of the members 49, 50 and 5I. If desired. one or more groundcontacting supports 54 may be positioned on the platform.

One or more latching means may be included in the assembly. The purposeof these latching means is to latch and to hold the platform in theraised position, so that once the platform has been raised, it may beheld in the raised position independent of pressure conditions withinthe cylinder. In one form, as shown in Figures 5 and 6, this latchingmeans includes a plate 55 secured to extensions 56 which are themselvesfastened to the cylinder I9. Pivoted upon the plate 55 is a latchmember'51 which may be notched, as at 58. The size of the notch is suchthat it embraces the reduced portion 26 of the piston rod 24. The latch51 is pivoted, as at 59. A spring 60 bears at one end against the edgeof the plate 55 and at the other end 6| against an enlargement 62, whichis formed as a' part of the latch. The enlargement is perforated, as at63, to receive an operating member 64. The operating member may be ofany desired shape or arrangement and may be so arranged that it can beoperated from the side of the vehicle or from any other point.

Another form of latch which is here sh'own, particularly in Figures 2and 3, may also be used. For this purpose a stirrup or loop-shapedmember 65 is mounted on each of the arms 34. As a means for mounting andsupporting this latch, a plurality of plates 66 may be used. Preferablyth'ere will be at least two of these plates, one at each side of theassembly. As shown in Figure 2, these plates are secured to the bodyframe members 3 and may also engage other parts oi.' the body. A shaft61 may extend `transversely and be supported in the plates 68 or inbearings mounted on those plates on each side of the assembly. 68, 68are latch members secured to the These members are mounted each toengage one of the stirrups 65. They are shown in the engaged position inFigure 2. A hand or operating lever 69 may be secured at any point onthe shaft 61, preferably adjacent one side of the assembly, as shown inFigure 3. Wh'en the platform is to be raised and lowered the hand lever69 will be operated to move the latch 68 out of engagement with thestirrups 65. When the platform is to be raised in the raised positionshown in full lines in Figure 2, it will be first raised to thatposition by the hydraulic mechanism, and the hand lever 69 will then bemoved to rotate the shaft @l to bring each of the latches $8 intoengagement with one of the stirrups 65. When that h'as beenaccomplished, the latches and stirrups are sufficient to hold theplatform in the elevated position, irrespective of any holding orraising eRort which might be exerted by the cylinder and pistonassembly. In fact, pressure can be entirely released from the cylinderwithout altering the position of the platform because the strength ofthe latches, stirrups and associated parts is such that they can holdthe platform in the raised'position. The use of the latch mechanism justdescribed, which includes in particular the means for mounting the latchmechanism on the body frame rather than on the chassis or vehicle frame,results in transferring a large part of the load of the total assemblyto the body frame, and results also in tieing the. body frame andchassis frame together. It is to be understood that ordinarily theplates 66 engagev only the body frame, but since a part of the hydraulicmechanism is carried from that frame when the parts are latched as shownin Figure 2,.

and since a part of the hydraulic mechanism is also carried from thevehicle or chassis frame, this form of latch and its associated partstransfers a. part of the weight of the hydraulic assembly to the bodyframe, while a part of the weight of the hydraulic assembly is stillcarried from the vehicle or chassis frame and in this sense, therefore,the latch and plate assembly ties the body and the chassis frametogether. While two forms of latches have been shown, it is to beunderstood that both may be used in a single installation or either maybe used alone.

Although I have shown an operative form of my invention, it will berecognized that many ch'anges in the form, shape, and arrangement ofparts can be made without departing from the spirit of the invention,and my showing is therefore to be taken as, in a sense, diagrammatic. Inparticular, the shape and arrangement of the platform might be widelyvaried and the particular form herewith shown is merely one suitableembodiment. Also th'e latches might be entirely omitted or either ofthem or both of them might be used. The safety overload device used incombination with the pump might be omitted or might be placed elsewherein the system, and.

the device as a wh'ole need not be mounted on an automotive vehicle. Itmight be mounted on any support.

This application is a continuation in part of my 'co-pending applicationNo. 492,230, led June 25, 1943, later abandoned. The use and operationof this invention vare as y follows:

`The device as shown is made up and may be assembled as a unit. It maythereafter be placed upon or attached to a vehicle or other support. Theentire assembly is carried from a single transverse member with theexception of the pump. The pump might also be mounted 'on the transversemember, but where it is to be driven surface. If now it be desired toraise the platform, the pump is operated and duid under pressure issupplied to the cylinder. The valve control is positioned to direct thefluid to the outer side of the piston, As pressure builds up within thepiston. the piston is drawn inwardly and carries with' it the pistonrod. The piston rod, since it is secured to a portion of the linkmechanism, as it is drawn in raises that mechanism and with it raisesthe platform. The height to which the platform is raised is controlledof course by the movement of the piston and this may be stoppedintermediate the limit at any desired point. If the platform is to becarried. clear to the top of its excursion, it will ordinarily be raisedto a point at which its upper surface is on a level with the uppersurface of the vehicle body floor. It may be held at that point eitherto discharge a load which has been previously put upon it or to take ona load from the vehicle body. If it is to be lowered, the valve isreversed and the piston is allowed to'move outwardly under the influenceof gravity to the dotted line position of the figure. This movement maybe continued to any degree between the upper and lower limits.

When the vehicle or other support is to be moved, the platform willordinarily be raised to its upper limit. The fluid pressure within thecylinder will usually be sufficient to hold it to that point. It isfrequently desirable, however, to provide other means for holding theplatform in the raised position, and the latches previously describedmay be used for that purpose. If the piston rod latch is present and isto be used, it

will be moved so that it engages the reduced portion of the piston rod.Thereafter, even if pressure is reduced within the cylinder, the pistoncannot move outwardly because the latch will be in contact with theshoulder formed at the reduced portion of the piston rod. At this pointthe larger portion.of the piston rod will bear against the latch, andthe latch will bear against the plate which is secured to the outer endof the cylinder. and the piston and piston rod cannot move further outof the cylinder, and hence the parts are maintained latched in theraised position.

If the other form of latch is to be used, it will be made and assembledas shown. In that case, when the parts are in the raised position, thehandle controlling the latches is manipulated,

and each of the latches engages its respective stirrup-like member.Thereafter diminution of pressure within the cylinder cannot permit theplatform and associated parts to move downwardly because the weight ofthese parts is largely taken by the latch and stirrup assembly, andthese members hold the platform in the raised position. This form oflatch assembly has the advantage that a substantial part of the weightof the platform and its raising means is now supported from the vehiclebody or the vehicle body frame, and this reduces the proportion of thetotal weight which must be carried by the chassis frame, and hencereduces the forces which would otherwise be acting to cause flexure ofthe chassis frame.

In the particular form of platform mechanism here shown, the platform isdesigned also to act as a tail gate. Whenthe parts are movedto theraised position and if desired latched in that position, the platform israised and becomes a closed tail gate. It may be raised upwardly to avertical position, pivoting about the rod 41 to which the outermost pairof arms or links is also joined. Once the platform has been raised tothe vertical position so that it can act effectively as a tail gate, itmay be fastened, locked or latched in that positionl in any desiredmanner. Ordinarily the body will have latching means by means of whichthe tail gate may be latched in the vertical position. When the platformis to be lowered again, it is unlatched from the body, moved to thehorizontal position and then if it is to be lowered to the ground, thelatch or latches for the raising mechanism are moved into inoperativeposition, and the platform may be lowered by proper manipulation of thecontrols of the hydraulic system.

I claim:

1. In combination, a vehicle frame and a body frame mounted thereon, amovable platform, a main unitary support secured to said vehicle frame,a plurality of links, each link supported at one end from said mainsupport and pivoted at its other end to said platform, a hydrauliccylinder supported from said main support, a piston therein, a pistonrod secured to said piston and secured to said links, means fordirecting fluid to the outer end of said cylinder, said means comprisinga valve control for said' cylinden' whereby the piston is positivelyforced in the raising direction within said cylinder, and means forsupplying fluid under pressure to said cylinder.

2. In combination, a vehicle frame and a body frame mounted thereon, amovable platform, a main unitary support secured to said vehicle frame,a plurality of links, each link supported at one end from said mainsupport and pivoted at its other end to said platform, a hydrauliccylinder supported from said main support, a piston therein, a pistonrod secured to `said piston and secured to said links, means fordirecting fluid to the outer end of said cylinder, said means comprisinga. valve control forsaid cylinder, whereby the piston is positivelyforced in the raising direction within said cylinder, means forsupplying fluid under pressure to said cylinder, and an overload checkin said fluid supplying means adapted, upon the occurrence of pressureabove a predetermined limit, to by-pass fluid away from said cylinder.

3. In combination, a vehicle frame and a body frame mounted thereon, amovable platform, a main unitary support secured to said vehicle frame,a plurality of links, each link supported at one end from said mainsupport and pivoted at its other end tor said platform, a hydrauliccylinder supported from said main support, va. piston therein, a pistonrod secured to said piston and secured to said links, means fordirecting fluid to the outer end of said cylinder, said means comprisinga valve control for said cylinder, whereby the piston is positivelyforced in the raising direction within said cylinder, means forsupplying fluid under pressure to said'cylinder,

whereby the lpiston is positively forced in the raising direction Withinsaid cylinder, means for supplying uid under pressure to said cylinder,and latch means for latching said platform in elevated position, saidlatch means including parts secured to said body and latch means adaptedto engage one or more of said links and to retain them and the platformwhich they carry in the elevated position without assistance from thehydraulic cylinder assembly.

5. In combination, a, vehicle frame and a body frame mounted thereon, amovable platform, a main support secured to said vehicle frame, aplurality of links, each link supported at one end from said mainsupport and pivoted at its other end to said platform, a hydrauliccylinder supported from said main support, a piston therein,

- a piston rod secured to said piston and secured to said links, meansfor directing fluid to the outer end of said cylinder, said meanscomprising a valve control for said cylinder, whereby the piston ispositively forced in the raising direction within said cylinder,means-for supplying fluid under pressure to said cylinder, an overloadcheck in said fluid supplying means adapted, upon the occurrence ofpressure above a predetermined limit, to br-passy fluid away from saidcylinder, and latch means for latching said platform in elevatedposition, said latch means including parts secured to said body andlatch means adapted 'to engage one or more of said links and to retainthem and the platform which they carry in the elevated position withoutassistance from the hydraulic cylinder assembly.

6. In combination, a vehicle frame and a body frame mounted thereon, amovable platform, a main support secured :to said vehicle frame, aplurality of pairs of links, each link pivotally supported at one endfrom said main support and pivoted at its other end to said platform, lahydraullc cylinder pivotally supported from said main support, a pistontherein, a piston rod secured to said piston and secured to said links,means for directing fluid to the outer end of said cylinder, said meanscomprising a valve control for said cylinder, whereby the piston ispositively forced in the raising direction within said cylinder, meansfor supplying fluid under pressure to said cylinder, an overload checkin said fluid supplying means adapted, upon the occurrence of pressureabove a predetermined limit, to by pass fluid away from said cylinder,and latch .means for latching said platform in elevated and latch meansfor latching said platform in g elevated position.

4. In combination, a vehicle frame and a body frame mounted thereon, amovable platform, a main unitary support secured to said vehicle frame,a plurality of links, each link supported at one end from said mainsupport and pivoted at its other end to said platform, a hydrauliccylinder supported from said main support, a piston therein, a pistonrod secured to said piston and secured to said links, means fordirecting uid to the outer end of said cylinder, said means comprising avalve control for said cylinder,

position, said latch means including parts secured to said body andlatch means adapted to engage one or more of said links and to retainthem and the platform which they carry in the elevated position withoutassistance from the hydraulic cylinder assembly.

7. Irl combination, a vehicle frame, a body frame supported therefrom, aplatform assembly for said body, and means for supporting said platformassembly, said means including a main support, a plurality of pairs oflinks, each link being pivoted at one end upon said support Vand pivotedat the other end upon said platform., and a hydraulic cylinder freelyswingable on said main support, a pistontherein, and a piston rodextending therefrom, means for securing said piston rod to said links,and a hydraulic system comprising a pump and hydraulic conduitsconnecting said lpump to said cylinder, and means associated with saidcylinder and adapted to direct pressure fluid to the outer end of saidcylinder.

a hydraulic system comprising a pump and hy- 8. In combination, avehicle frame, a body frame supported therefrom, a platform assembly forsaid body, and means for support-ing said platform assembly, said meansincluding a main support, a plurality of pairs of links, each link beingpivoted at one end upon said support and pivoted at the other end uponsaid platform and a hydraulic cylinder freely swingable o n said mainsupport, a piston therein, and a piston rod extending therefrom, meansfor securing said piston rod to said links, and a hydraulic systemcomprising a pump and hydraulic conduits connecting said pump to saidcylinder, and means associated with said cylinder and adapted to directpressure fluid to the outer end of said cylinder, and latch meanspositioned upon said body and including a latch and means for moving itto engage said links and to retain the same in the position ofelevation, irrespective f pressure conditions within the cylinder.

9. In combination, a vehicle frame, a body frame supported therefrom, aplatform assembly for said body, and means for supporting said platformassembly, said means includinga main support, a plurality of pairs oflinks, each link being pivoted at one end upon said support and pivotedat the other end upon said platform, and a hydraulic cylinder on saidmain support, a piston therein, and a piston rod extending therefrom,means for securing said piston rod to said links, and a hydraulic systemcomprising a pump and hydraulic `conduits connecting said pump to saidcylinder, and means associated with said cylinder and adapted to directpressure fluid to the outer end of said cylinder, and latch meanspositioned upon said cylinder and including a part adapted, when theplatform is in"the raised position, to engage the piston rod and toretain the same in the position of elevation, irrespective of pressureconditions within the cylinder.

10. In combination, a vehicle frame, a body frame supported therefrom, aplatform assembly for said body, and means for supporting said platformassembly, vsaid means including a main support, a plurality of pairs oflinks, each link being pivoted at one endupon said support and pivotedat the other end upon said platform, and a hydraulic cylinder on saidmain support, a piston therein, and a piston rod lextending therefrom,means for securing said piston rod to said links, and a hydraulic systemcomprising a pump and hydraulic conduits connecting said pump to saidcylinder, and means associated with said cylinder and adapted to directpressure fluid to the outer end of said cylinder, and latch meanspositioned upon said body and including a latch and means for moving itto engage said links, and latchA means positioned upon said cylinder andincluding a part adapted, when the platform is in the raised position,to engage the piston rod and to retaingthe same in the position'ofelevation, irrespective of pressure conditions within the cylinder.

11. In combination, a vehicle frame, a body frame supported therefrom, aplatform assembly for said body, and unitary means for supporting saidplatform assembly as a unit, said means including a main support, a.plurality of `pairs of links, each link being pivoted at one end uponsaid support and pivoted at the other end upon said platform, and ahydraulic cylinder swingable on said main support, a piston therein, anda piston rod extending therefrom, means for securing said piston rod tosaid links, said cylinder and piston mounted to swing with said linksand draulic conduits connecting said pump to said cylinder, an overloadrelease positioned in communication with said hydraulic system, andadinstable means in said overload release adapted, upon the occurrenceof pressure above a predetermines limit within sai hydraulic system, toby-pass fluid away from said cylinder.

12. In combination, a vehicle frame, "a body frame supported therefrom,a platform assembly for said body, and unitary means for supporting saidplatform assembly as a unit, said means including a main support, a pairof ldownwardly depending parts secured thereto, a plurality o! pairs oflinks, each link being pivotedv at one end upon said downwardlydepending parts and pivoted at the other end upon said platform, and ahydraulic cylinder swingable on said main support, a piston therein, anda. piston rod extending therefrom, means for securing said piston rod tosaid links, saidv cylinder and piston mounted to swing with said linksand a hydraulic system `comprising a pump and hydraulic conduitsconnecting said pump to said cylinder, and means associated with saidcylinder and adapted to direct pressure iiuid to the outer end of saidcylinder.

13. In combination, a vehicle frame, a body frame supported therefrom, aplatform assembly for said body, and unitary means for supporting saidplatform assembly as a unit, said means including a main support, a pairof downwardly depending parts fixed thereto, a plurality of pairs oflinks, each link being pivoted at one end upon said downwardly dependingparts below said vehicle frame, and pivoted at the other end upon saidplatform, and a hydraulic cylinder pivoted on said main support, apiston therein, and a piston rod extending therefrom, means forpivotally securing said piston rod to said links,w and a hydraulicsystem comprising a pump and hydraulic conduits connecting said pumpto'said cylinder, and means associated withsaid cylinder and adapted todirect pressure fluid to the outer end of said cylinder.

14. In combination, a vehicle frame, a body frame supported therefrom, aplatform assembly for said body, and unitary means for supportingsaidplatform assembly as a unit, said means includmg a main support, apair of downwardly depending parts fixed thereto, a plurality of pairsof links, each link being pivoted at one end upon said downwardlydepending parts below said vehicle frame and pivoted at the other endupon said platform, and a hydraulic cylinder pivoted on said mainsupport, a piston therein, and a piston rod extending therefrom, meansfor pivotally securing said piston rod to said links, and ahydraulic'system comprising a pump and hydraulic conduits connectingsaid pump to said cylinder, an overload release positioned incommunication with said hydraulic system, and ad- `instable means insaid overload release. adapted, upon. the occurrence of pressure above apredetermined limit within said hydraulic system, to by-pass uid awayfrom said cylinder, and means associated with said cylinder and adaptedto direct pressure uid to the outer end of said cylinwardly dependingparts and pivoted at the other end upon said platform, and a hydrauliccylinder pivted on said main support, a piston therein, and a piston rodextending therefrom, means for pivotally securing said piston rod tosaid links', and a hydraulic system comprising a pump and hydraulicconduits connecting said pump to said cylinder, an overload releasepositioned in communication with said hydraulic system, and adjustablemeans in said overload release adapted, upon the occurrence of pressureabove a predetermined limit within said hydraulic system. to by-passfluid away from said cylinder, and valve means associated with saidcylinder and adapted to direct pressure fiuid .to the outer end of saidcylinder, and latch means positioned upon said body and including alatch and means for moving it to engage said links, and latch meanspositioned upon said cylinder and including a part adapted, when thetail gate is in the raised position, to engage the piston rod and toretain the same in the position of elevation, irrespective of pressureconditions within the cylinder.

16. In combination, with a vehicle having a chassis frame and a bodyframe supported thereon, an elevating assembly comprising a unitary,inain supporting member adapted to be attached to said chassis frame,and carrying an elevating assembly including an'elevating platform,links pivoted upon said supporting member and said platform, a hydraulichoisting assembly pivoted on said main support and pivotally joined tosaid links, whereby the links and the platform are raised and lowered,and latch means secured to said body frame and adapted to engage saidlinks and to support them and said platform in the raisedposition, andmeans for supplying pressure uid to the outer end of the hydrauliccylinder, and an overload check associated with said pressure fluidsupplying means and adapted, upon the occurrence of pressure above apredetermined limit, to by-pass fluid away from said cylinder.

17. In combination with a vehicle having a chassis frame and abodyframe, a unitary elevating assembly, means whereby it can be removablymounted thereon as a unit and comprising a, main supporting member,means for securing said supporting member to the chassis frame, thesupporting assembly including also links and a movable platform, thelinks being pivoted upon the supporting member and to the platform,hydraulic means movably mounted on the support and attached also to thelinks and adapted to swing with the movement of said links,.means forsupplying pressure fluid to the hydraulic assembly, and latching meansadapted to latch the platform in theA raised position, said latchingmeans being secured to the body frame.

LESTER W. WACHTER.

